<!DOCTYPE html>
<link rel='match' href='position_relative_stacking_context_ref.html'>
<style>
body, html {
    margin: 0;
}
div {
    width: 100px;
    height: 100px;
}
#a {
    position: relative;
    z-index: 2;
    background: green;
}
#b {
    position: absolute;
    background: red;
    top: 0;
    left: 0;
}
</style>
<div id=a></div>
<div id=b></div>

